JPS6020844B2 - heat resistant electrical insulation - Google Patents

Description

[Detailed description of the invention] The present invention relates to novel heat resistant electrical insulators.

Conventionally, heat-resistant electrical insulators have been manufactured by bonding a base material such as asbestos with a binder such as low-melting point glass, or by bonding a metal oxide such as alumina with silica oxide. They were manufactured by adding competitive setting promoters as necessary. Among these, the so-called "micalex", in which mica powder is adhered to a boric acid-lead based low-dispersion point glass, is widely known. Micalex has excellent heat resistance and electrical insulation properties, but during manufacturing, it is necessary to apply pressure of about 200 to 1000 k9' while heating it to a temperature above the softening temperature of the low melting point glass, that is, 500 to 800 k9'. However, since the process is extremely complicated, the manufacturing cost is high. In addition to this, there is also the drawback that a reaction progresses between the mother-in-law and the glass during bonding, and the mica is eroded into the glass, resulting in a decrease in workability. In addition to low-melting glass, phosphoric acid, phosphates such as primary phosphates of metals, sols such as alumina sol and silica gel, and cement are used as binders for insulation bases. . However, when phosphoric acid or a phosphoric acid-based binder such as phosphates is used alone, an electrical insulator with excellent heat resistance (400 to 50 and 0) and nonflammability can be obtained, but it is resistant to water and moisture. The disadvantages are that the electrical properties at the time are poor, and the binding effect is reduced due to the chemical reaction between the insulating base material and the phosphoric acid binder, making it difficult to obtain uniform molded products. Furthermore, a binder made only of phosphoric acid mixed with an organic binder made of thermosetting resin may be used as a binder, but in this case, decomposition of the organic binder woke up early,
Molding was sometimes difficult. Also, alumina sol,
Sol-based binders such as silica gel have a 100%
It required high temperature treatment of about 0 to 1200 qo and had the same problem as Micalex.

Furthermore, cement-based binders have the disadvantage that they are difficult to use in combination with thermosetting resins, making it difficult to obtain delicate products. On the other hand, insulating porcelain made by firing metal oxides such as alumina and beryllia is mainly intended for insulation under conditions such as high voltage, high frequency, and high temperature.

However, these electrically insulating porcelains have the disadvantage that they need to be fired at a fairly high temperature during production, and are not easy to process into the desired shape, making it difficult to obtain dimensional accuracy and mechanical problems such as impact resistance. Insulating porcelain that is fully satisfactory has not been obtained because some of them have drawbacks such as low mechanical strength or toxicity.In order to solve these drawbacks, the inventors of the present invention have conducted extensive research. Results Zinc oxide, titanium oxide, magnesium oxide, anaerobic compounds obtained by heating a mixture containing at least one koji compound selected from the group consisting of calcium oxide and barium oxide to a temperature of 600 qo or higher and boric acid as essential components. A composition containing at least one of inorganic fibers, an inorganic filler, or a thermomagnetic resin in addition to the above composition components is heated under pressure to bind the composition. By binding, it improves the mechanical properties,
It has been discovered that an electrical insulator with excellent heat resistance can be obtained, and this heat-resistant electrical insulator is described in detail in the patent application specification entitled "Heat-resistant electrical insulator (0)" dated the same date as the present application. ing.

However, the primary molded product obtained by binding the above composition by heating under pressure, and the secondary molded product obtained by further heat-treating the primary molded product, do not require long-term Hinazu treatment. It was found that when this process was carried out, the electrical properties and mechanical properties deteriorated somewhat, and a solution to this problem was desired since an electrical insulator with even higher water resistance was desired depending on the application.

In order to solve this problem, the present inventors conducted intensive research and found that 'a} (i) zinc oxide source, (ii) titanium oxide source and (
iii] A fired product obtained by heating a mixture consisting of at least one compound selected from the group consisting of a magnesium oxide source, a calcium oxide source, and a barium oxide source to a temperature of 600°C or higher, 'b' boric acid and {c) A composition containing an acidic metal phosphate or an acidic condensed phosphate as an essential component (hereinafter this composition is referred to as a binder) is bound by heating under pressure, or a binder In addition to the ingredients {d)
By heating and bonding a composition containing at least one material selected from the group consisting of inorganic fibers, inorganic fillers, and thermosetting resins, scaly properties, mechanical properties, and heat resistance bending can be improved. It was discovered that an electrical insulator with excellent water resistance and excellent water resistance could be obtained.
The present invention has finally been completed. The fired product used in the present invention is manufactured as follows.

That is, a zinc oxide generating source containing zinc oxide, preferably 100 mesh or less, which produces zinc oxide by heating, a titanium oxide generating source, preferably 100 mesh or less, containing titanium oxide, producing titanium oxide by heating, and -oxidation. A magnesium oxide source that produces each of these oxides by heating, including magnesium, calcium oxide, and barium oxide.A magnesium oxide source that produces each of these oxides by heating. The mixture was heated in a heating furnace such as an electric furnace for 6 hours.
Temperature above 00℃, preferably 700-1400℃~
The desired fired product can be obtained by heating and firing, preferably at a temperature of 900 to 1300°C for about 15 to 3 minutes. If the above-mentioned firing temperature is less than 600 qo, it is not preferable because it takes too much time to obtain a fired product.

However, even if it is less than 600 qo, a desired fired product can be obtained by firing for a considerably long time. In this specification, "...a mixture consisting of a zinc oxide source, (ii) a titanium oxide source, and (ii) at least one selected from the group consisting of a magnesium oxide source, a calcium oxide source, and a barium oxide source at 600 ° C. A fired product obtained by heating to a temperature above means that a zinc oxide source becomes zinc oxide when heated, a titanium oxide source becomes titanium oxide when heated, and a magnesium oxide source, calcium oxide source, and barium oxide source change when heated. Magnesium oxide, calcium oxide, barium oxide, and at least a portion of (i) zinc oxide, (ii) titanium oxide, and (j
ii) It means something obtained by causing some kind of reaction with at least one of magnesium oxide, calcium oxide, or barium oxide by heating (for example, a solid lacquer of each of the above components), but a mere mixture of the above components is Not included.

In addition to zinc oxide, zinc oxide sources for producing baked products include, for example, zinc hydroxide, zinc carbonate, basic zinc carbonate, zinc nitrate, zinc acetate, and the like.

In addition to titanium oxide, titanium oxide sources include, for example, titanium hydroxide. Furthermore, sources of magnesium oxide, calcium oxide, and barium oxide include magnesium oxide, calcium oxide, and barium oxide, as well as hydroxides, carbonates, talates, and organic acid salts of the respective metals. It will be done. When producing the competitive product used in the present invention, the mixing ratio of each raw material component can be varied over a wide range depending on the purpose of the electrical insulator to be obtained. The mixing ratio of zinc oxide is usually 70 to 30 mol%.
, titanium oxide is preferably in the range of 30 to 70 mol%.

The mixing ratio of the alkali metal oxides is 1 part to 10 parts of the total amount of zinc oxide and titanium oxide.
A range of $3 parts is preferred, especially a range of 2 parts to 15 parts. Alkali metal oxides are effective in preventing blistering when primary molded products are heat-treated and processed into secondary molded products, but when the amount of alkali metal oxides is less than 1 part. is not very effective in preventing blistering, and if the number is more than 3, there is a tendency for the water resistance of the electrical insulator to decrease. The boric acid used together with the fired product in producing the heat-resistant electrical insulator of the present invention has a molar ratio of 1:0 to the total number of moles of zinc oxide and titanium oxide contained in the fired product.
It is preferably in the range of 1 to 8.0.

If the proportion of boric acid used is less than 0.1, the resulting electrical insulator will have insufficient mechanical strength, and if the proportion of boric acid used is 8.0 or more, the resulting electrical insulator will have insufficient mechanical strength. Unfavorable in terms of water resistance. Note that within the range of the above-mentioned usage ratio of boric acid, a part of the boric acid can be replaced with boron oxide. Moreover, changing the layers can be useful for suppressing the occurrence of blistering when a primary molded product is heat-treated and processed into a secondary molded product. Also, add 1 boric acid
A dehydrated condensate of boric acid, the main component of which is metaboric acid, obtained by heating at a temperature of 0.0 ppm or more can also be used in place of boric acid. Therefore, in this specification, "boric acid" includes not only boric acid alone, but also boric acid in which a portion of boric acid is layered with boron oxide or metaboric acids. In addition, in this specification, the moles of zinc oxide and titanium oxide in the fired product are used in the following meanings. That is, if a fired product is produced using, for example, 60 days of zinc oxide as the zinc oxide source, 40 hours of titanium oxide as the titanium oxide source, and 52 hours of calcium oxide as the magnesium oxide source, the scale formation will be substantially 1059. When a substance is obtained and the zinc oxide contained therein is converted into moles, the amount of zinc oxide (60 / molecular weight of zinc oxide (31. spots) =
It becomes 0.737 mol, and when titanium oxide is converted to the number of moles,
Amount of titanium oxide (40) / Molecular weight of titanium oxide (79)
．． 90) = 0.501 mole, and converting calcium oxide into moles, the amount of calcium oxide (5/molecular weight of calcium oxide (5608) = 0.089 mole. Therefore, this fired product 105 times is 0. .737 ten 0.50
100. For convenience, it can be considered that female 9 is equivalent to 1.327 moles. On the other hand, since it can be considered that 1 mole of boric acid is 61.8 moles, the number of moles of boric acid relative to the total number of moles of zinc oxide and titanium oxide contained in the fired product is 0.
can be mixed in a desired molar ratio based on the above-mentioned concept. Next, the oxidized IJ acid metal salt or acidic condensed IJ acid metal salt used in the present invention is a metal salt in which at least one hydroxyl group directly bonded to the phosphorus atom of phosphoric acid or condensed phosphoric acid remains. Specific examples thereof include monobasic aluminum phosphate, monobasic magnesium phosphate, monobasic calcium phosphate, monobasic zinc phosphate, monobasic steel phosphate, monobasic iron phosphate, Monophosphates such as manganese monophosphate and zirconium monophosphate, dibasic phosphates such as dibasic aluminum phosphate, dibasic magnesium phosphate, and dibasic calcium phosphate, and sesquiphosphates such as aluminum sesquiphosphate. , pyrophosphates such as aluminum pyrophosphate and calcium pyrophosphate.

Further examples include acidic condensed phosphates obtained by heating and dehydrating the primary phosphate alone or in combination with other acidic metal phosphates preferably at a temperature of 120 to 300 qo. If the total weight of the above baked product and boric acid is 99 to 7% by weight, the acidic metal phosphate or acidic condensed phosphate used in the present invention is 1 to 3% by weight. It is preferable to use within the range of .

If the amount of acidic phosphate or acidic condensed phosphate is less than 1% by weight, it will not be very effective in improving the water resistance of the resulting electrical insulator, and if it is more than 3% by weight, the water resistance will actually decrease. In addition to the fact that there are cases where glass fibers are used as a molding material component, there is a tendency for glass fibers to deteriorate. In the present invention, by suturing and using (i) boric acid and (ii) acidic metal phosphate or acidic condensed phosphate as the acidic component of the binder, as described above, a totally unexpected result can be obtained. A heat-resistant electrical insulator that also has water resistance is obtained.

Furthermore, when using a rough combination of 1 (i) boric acid and (ii) acidic metal phosphate or acidic condensed phosphate, the following effects are expected. However, as will be explained later, this water becomes a gaseous substance and evaporates, so it would be desirable if the evaporation of this water could be reduced in some way.However, in general, phosphates are Moisture is required to act as a binder, so if phosphate is used in combination with boric acid, the moisture generated by the decomposition of boric acid will act as a binder for the phosphate. Therefore, the water generated from boric acid is effectively used for phosphate, and it is expected that the amount of transpiration will be reduced as water vapor.Inorganic fibers used in the present invention include, for example, glass cloth and glass mat. , asbestos vapor, asbestos, ceramic fiber, potassium titanate fiber, etc.

Examples of inorganic fillers used in the present invention include calcium oxide, tin oxide, magnesium oxide, aluminum oxide, zinc oxide, titanium oxide, silicon oxide, iron oxide, zirconium oxide, calcium hydroxide, aluminum hydroxide. , iron hydroxide, aluminum chloride,
Magnesium fluoride/HoY, glass powder, zirconium silicate, kaolin, calcined clay "barium titanate"
Talc, mica, mullite, zircon sand,
Examples include whitebait/ゞrune, /ゞ-miyukiyulite, barlite, etc.

Furthermore, the thermosetting resin used in the present invention includes, for example, phenol resin, epoxy resin, silicone resin,
Examples include polyimide resin, melamine resin, and polyester resin.

In the present invention, in addition to the binder component, the above-mentioned inorganic fibers,
By heating a composition containing at least one material selected from the group consisting of a permanent filler and a thermosetting resin under pressure to bind it, the binder alone can be heat-treated under pressure. It is possible to obtain electrical insulators with a wider range of physical properties than the electrical insulators that can be obtained.

For example, by heating and bonding a mixed system of a binder, inorganic fibers, and/or inorganic filler under pressure, mechanical properties may be better depending on the application than those made with just the binder. A more preferable electrical insulator is obtained. In addition, by heating a mixture of a binder and a thermosetting resin under pressure to bind it together, although the heat resistance is generally inferior to that obtained by binding only a binder, it is possible to Depending on the composition of the binder, the binding Although it can vary widely depending on the type of components other than the agent and the use of the resulting electrical insulator, it is usually electrical insulator 1.
With respect to 0 parts by weight, the binder is preferably in the range of 5 to 99.8 parts, and the components other than the binder are in the range of 95 to 0.2 parts. If the amount of the binder is less than 5 parts, the mechanical strength of the resulting electrical insulator will be reduced, and if it is more than 99.8 parts, it will be difficult for the components other than the binder to exhibit their intended effects. The method for manufacturing a heat-resistant electrical insulator according to the present invention will be explained below.

First, a zinc oxide source such as finely ground zinc oxide, a titanium oxide source such as titanium oxide, and at least one compound of an alkali metal oxide source such as the above-mentioned alkali metal oxides. Mix evenly in the desired proportions,
Then a temperature of 600 qo or more, preferably 600 to 14
A baked product is prepared by heating and baking at 00°C for about 150 hours to 30 minutes, more preferably at 900 to 1300°C for about 5 hours to 1 hour. The obtained baked product is pulverized, a desired amount of boric acid and a desired amount of an acidic metal phosphate or an acidic condensed phosphate are mixed therein, and this mixture is further pulverized to a size of 100 mesh or less using a ball mill or the like. A molding composition consisting only of the above-mentioned binder is obtained.A composition containing at least one of an inorganic filler or a thermosetting resin in addition to the binder is obtained by combining each of the above-mentioned components of the binder with an inorganic filler or a thermosetting resin. It is prepared by mixing a desired amount of at least one type of thermosetting resin and then pulverizing it to 100 mesh or less using a ball mill or the like.The molding composition containing inorganic fibers is
It is prepared by uniformly spraying the various molding compositions described above on inorganic fibers. The molding composition obtained as described above is put into a mold and molded at a molding temperature of 130 to 20,000°C.
The material is heated and pressed for about 10 to 6 minutes under a molding pressure of 300k9' to obtain a heat-resistant sagaki insulator.

A molding temperature of 130 qo or lower is not preferable because the strength of the obtained insulator decreases;
If it is more than that, dehydration of boric acid will occur rapidly, causing foaming, which is not preferable.

If the molding pressure is less than 100k9', it is not preferable because a dense insulator cannot be obtained, and if the molding pressure is more than 300k9', there is no change in the properties of the obtained insulator, and the effect of applying high pressure is Not particularly. When heat-resistant electrical insulators are manufactured under heated and pressurized conditions, gaseous substances are generated due to thermal decomposition of boric acid or thermosetting resin contained in the binder. It is preferable to temporarily release the pressure applied to the gas for degassing.
The molding time varies depending on the molding temperature and molding pressure, but is approximately 10 to 6 minutes. After the electrical insulator has been obtained in this way, it is heated under pressure or without pressure, preferably within a temperature range of 500°C above the molding temperature, in order to obtain dimensional stability, depending on the purpose and conditions of use. It is desirable to post-process for about 24 hours. The present invention will be explained below with reference to examples, but the present invention is not limited to the following examples.

Example A product obtained by uniformly mixing 5 parts by weight of calcium oxide of 200 mesh or less with 10 parts by weight of a mixture containing zinc oxide of 1200 mesh or less and anatase titanium oxide of 300 mesh or less at a molar ratio of 2:1. The resulting mixture was heated and fired in an electric muffle furnace at 120 mm for more than 2 hours to obtain an almost colorless, semi-molten hard fired product consisting of zinc oxide, titanium oxide, and calcium oxide.

This fired product was pulverized to 200 mesh or less using a candle picker. 70 parts of this fired product, 25 parts of boric acid pulverized to 200 mesh or less, and 25 parts of boric acid pulverized to 200 mesh or less
A molding composition consisting only of a binder was obtained by uniformly mixing with 5 parts of aluminum phosphate. Approximately 50 quarts of this molding composition was put into a round mold with a diameter of 9 quarts, with an overflow of 170 quarts, and a
The mixture was bonded by heating under a pressure of 0.00 kg/ground for about 1 hour.

During this time, the pressure applied to the molded product was released and degassing was performed for 7 times for 1 minute. The primary molded product thus obtained was heat-treated at 300 oo for 5 hours as a post-treatment.
A secondary molded product with a thickness of about 3 mm for physical property evaluation was obtained. No blistering phenomenon was observed in the molded product obtained under such molding conditions. Furthermore, this molded product was significantly easier to process into a desired shape than conventional alumina porcelain insulators. Example 2 A fired product consisting of zinc oxide, titanium oxide, and magnesium oxide was treated in the same manner as in Example 1 except that 5 parts by weight of magnesium oxide was used instead of 5 parts by weight of calcium oxide in Example 1. I got something.

After making a mixture of 7 parts of this fired product, 25 parts of boric acid, and 5 parts of primary aluminum phosphate to a mesh size of 200 mesh or less,
Molding and post-treatment were performed in exactly the same manner as in Example 1 to obtain a secondary molded product with a thickness of about 3 ribs for evaluation of physical properties. Example
3 A mixture of the fired product 7 obtained in Example 1, 25 parts of boric acid, and 5 parts of monobasic calcium phosphate was reduced to 200 mesh or less, and then molded and post-treated in exactly the same manner as in Example 1. A secondary molded product with a thickness of about 3 legs for physical property evaluation was obtained.

Example 4 A mixture of 7 parts of the fired product obtained in Example 1, 25 parts of boric acid, and 5 parts of monobasic zinc phosphate was reduced to 200 mesh or less, and then molded and post-treated in exactly the same manner as in Example 1. As a result, a secondary molded product with a thickness of about 3 yen for physical property evaluation was obtained.

Example 5 7 pieces of rock obtained in Example 1, 25 parts of boric acid, 2.5 parts of monobasic aluminum phosphate, and 2 parts of monobasic zinc phosphate
．． After reducing the 5 parts of the mixture to 200 mesh or less, molding and post-treatment were carried out in exactly the same manner as in Example 1 to obtain a mixture with a thickness of approximately 3.
A secondary molded product for evaluating the physical properties of the ribs was obtained.

Example 6 Primary aluminum phosphate was dehydrated by heating at 180 oo for 2 hours to obtain acidic condensed aluminum.

A mixture of the fired product 7 Bodu obtained in Example 1, 25 parts of boric acid, and 5 parts of the above acidic condensed aluminum phosphate was added to 200
After reducing the size to below mesh, molding and post-treatment were carried out in exactly the same manner as in Example 1 to obtain a secondary molded product with a thickness of approximately 3 willow for physical property evaluation. Example 7 A uniform mixture of 200 mesh or less of monobasic aluminum phosphate and monobasic calcium phosphate in equal amounts was 190
The mixture was heated and dehydrated at ℃ for 2 hours to prepare an acidic condensed phosphate metal salt.

A mixture of the scale product 7 obtained in Example 1, 25 parts of boric acid, and 5 parts of the above acidic condensed phosphate metal salt was reduced to 200 mesh or less, and then molded and post-treated in exactly the same manner as in Example 1. As a result, a secondary molded product with a thickness of about 3 yen for physical property evaluation was obtained. Example 8 A molding composition containing an inorganic filler was prepared by uniformly mixing 9 parts of the molding composition powder prepared in Example 1 and 10 parts of mica of 200 mesh or less.

This molding composition was molded and post-treated in exactly the same manner as in Example 1 to obtain a secondary molded article with a thickness of approximately 3 skins for evaluation of physical properties. Example 9 A thermosetting resin-containing molding composition was prepared by uniformly mixing 95 parts of the molding composition powder prepared in Example 1 and 5 parts of a pulverized epoxy resin of 200 mesh or less.

This molding composition was molded using exactly the same machine as in Example 1 to obtain a primary molded product. The primary molded product was heat treated in an electric furnace at 200 qo for 5 hours and post-treated to obtain a secondary molded product for evaluation of physical properties.

Example 10 Glass chopped strand pine cut into 150 x 150 ribs was prepared, and molding composition powder consisting only of the binder prepared in Example 1 was sprinkled on each mat, and the top and bottom were Two glass cloth mats were stacked on top of each other in a thin layer.

The amount of spraying was the same as the total weight of glass fibers. The obtained laminate was placed in a mold, set at a temperature of 170 qo, and heated for 20 qo.
Pressure and heat treatment was performed for 4 minutes at a pressure of 0 k9/ground.
During this time, the pressure applied to the molded product was released and degassing was performed several times for 1 minute each. The primary molded product thus obtained was heat treated at 300 qo for 5 hours to obtain a secondary molded product for physical property evaluation. Example 11 94 parts of the molding composition powder consisting only of the binder prepared in Example 1, 1 part of epoxy resin pulverized to 200 mesh or less, and 2 parts of thermosetting silicone resin pulverized to 200 mesh or less. 53 parts of the mixed powder obtained by uniformly mixing the three materials was sprinkled on 4 pieces of glass fiber in exactly the same manner as in Example 10, and the obtained laminate was molded in the same manner as in Example 10. A next molded product was obtained.

The primary molded product was heat treated at 200 qo for 5 hours to obtain a secondary molded product for physical property evaluation.

Reference Example 1 A mixture obtained by uniformly mixing the baked product 7 prepared in Example 1 with 25 parts of boric acid of 200 mesh or less was molded and post-treated in exactly the same manner as in Example 1. ,
A sample for physical property evaluation was obtained for comparison.

Table 1 shows the physical property values obtained for each electrical insulator thus obtained.

Table 1

Claims (1)

[Scope of Claims] 1 (a) At least one member selected from the group consisting of (i) a zinc oxide source, (ii) a titanium oxide source, and (iii) a magnesium oxide source, a calcium oxide source, and a barium oxide source. A composition containing as essential components (b) boric acid, and (c) an acidic metal phosphate or an acidic condensed phosphate. A heat-resistant electrical insulator made by heating and bonding under pressure. 2 (a) A mixture consisting of (i) a zinc oxide source, (ii) a titanium oxide source, and (iii) at least one compound selected from the group consisting of a magnesium oxide source, a calcium oxide source, and a barium oxide source. (d) boric acid, (c) acidic metal phosphate or acidic condensed phosphate, and (d) inorganic fiber,
A heat-resistant electrical insulator obtained by heating and bonding a composition containing at least one selected from the group consisting of an inorganic filler and a thermosetting resin as an essential component under pressure.